Unexpected nongenetic individual heterogeneity and trait covariance in Daphnia and its consequences for ecological and evolutionary dynamics

Clayton E. Cressler, Stefan Bengtson, William A. Nelson

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Individual differences in genetics, age, or environment can cause tremendous differences in individual life-history traits. This individual heterogeneity generates demographic heterogeneity at the population level, which is predicted to have a strong impact on both ecological and evolutionary dynamics. However, we know surprisingly little about the sources of individual heterogeneity for particular taxa or how different sources scale up to impact ecological and evolutionary dynamics. Here we experimentally study the individual heterogeneity that emerges from both genetic and nongenetic sources in a species of freshwater zooplankton across a large gradient of food quality. Despite the tight control of environment, we still find that the variation from nongenetic sources is greater than that from genetic sources over a wide range of food quality and that this variation has strong positive covariance between growth and reproduction. We evaluate the general consequences of genetic and nongenetic covariance for ecological and evolutionary dynamics theoretically and find that increasing nongenetic variation slows evolution independent of the correlation in heritable life-history traits but that the impact on ecological dynamics depends on both nongenetic and genetic covariance. Our results demonstrate that variation in the relative magnitude of nongenetic versus genetic sources of variation impacts the predicted ecological and evolutionary dynamics.

Original languageEnglish (US)
Pages (from-to)E13-E27
JournalAmerican Naturalist
Volume190
Issue number1
DOIs
StatePublished - 2017

Keywords

  • Daphnia pulicaria
  • Demographic heterogeneity
  • Individual stochasticity
  • Individual-based model
  • Lifehistory covariation
  • Stoichiometric food quality

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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